Telephone-exchange system.



S. B. WILLIAMS, JR, & E. H. CLARK.

'TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR. 21.191]- Pate'nted Feb. 12, 1918.

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3 SHEETS-SHEET] S. B. wlLLlAM JR. & E. H. CLARK.

TELEPHONE EXCHANGE SYSTEM.

I APPLICATION FILED MAR. 21.1917- 1,256,0'Z. Patented Feb. 12,1918.

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Edgar H. C/m /r.

S. B. WILLIAMS, JR. & E. H. CLARK.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED MAR. 21.1917.

Patented Feb. 12, 1918.

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- H a ass Parana? -Q SAMUEL B. WILLIAMZS, JR, OF BROOKLYN, A

ASSIGNORS T0 WESTERN ELECTRIC COMPANY, INCORPORATED, OF N A CORPORATION OF NEW YORK.

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m) EDGAR H. citanx, or new TELEPHONE-EXCHANGE sirsrnm.

To all whom it may concern:

Be it known that we, SAMUEL B. WIL- LIAMs, Jr, and EDGAR H. CLARK, citizens of the United States, residing at Brooklyn, in the county of Kings and State ofNew York, and at NewYork, in the county of New York and State of New York, respectively, have invented certain new and useful Improvements in Telephone-Exchange Sys tems, of which the following is a full, clear, concise, and exact description. 7 This invention relates to an improved telephone exchange system, and has particu larly to do with an improved organization for automatically controlling the distribution of calls in a telephone call distributing system. Tn present .day telephone systems, there is a considerable diversity in the lines of an exchange with respect to their character and the sort of service they are given. Some of the lines may be provided with coin boxes at the subscribers stations, and in serving such lines the operatormust be provided with apparatus for enabling her to collect the coin if the connection is completed, or to return the coin if the connection is not completed. Another class of lines may in- .volve the writing of a charge. ticket by the operator for every connection completed. Another class may require the manipulation of apparatus by the operator that causes a charge to be made upon a message register or counter associated with each line. Another class of lines may be given a so-called flat rate for the calls originated, and in the case such 'lines the operator is not required to perform any special act. The lines of the telephone exchange'may include individual or single station lines, party lines, and lines extending to private branch exchange switchboards-the so-called PBX lines. Othr lines of the exchange may extend to pay stations, another sort of service. I

It is the particular object of the present invention to increase the operating efiiciency of a telephone exchange of this sort by providing an organization that will operate automatically to segregate the calls originated by lines of the various classes and di rect the calls of each class to operators positions particularly assigned and adapted to the giving of the corresponding sort of serv- Specification of Letters Patent.

Application filed March 21, 1917. Serial No. 158,278.

and thus require still Patented Felt.a 112, 391%..

ice. Thus the calls initiated by coin-collector lines may automatically be irected to one operators position, the calls initiated by the measured service lines may automatically be directed to another operators posi tion, the calls initiated by the flat rate lines may automatically be directed to another operators position, and so on for all of the various classes of lines. The work of each operator is thus specialized, with a corresponding increase in efficiency. The special apparatus for performing the special acts required in connection with the serving of certain classes of lines furthermore need be provided only upon those positions that are assigned to such special service.

Obviously, of course, the segregation need not be carried to the point where the calls of each of the classes are directed to a different operators position; and the preferred embodiment in connection with which the invention is herein disclosed merely provides for the automatic segregation of the calls into two classes. But merely by an extension of the principle exercise of further invention, the segrega tion of the classes may be carried to any de gree of subdivision that may be deemed desirable.

When the calls from a number of classes ,of lines are divided, as in the present instance, into two main classes with respect to their segregation to certain operators positions it is desirable that such positions be provided with devices for automatically informing the operator as to which class, of the several classes her position serves, the particular line that is calling belongs. The present invention provides for the association with the lines of each class of identifying means to which both the automatic segregating mechanism and the automatic indicating devices are selectively responsive, so that the calls from the lines of the various classes are automatically distributed among the operators positions in accordance with the sort of service the positions are adapted to give, and so that the character of the calling line and its class of service are automatically indicated to the operator.

The invention in its preferred embodiment will be described in connection with the accompanying drawings, and 3, taken together, and with Fig. 1 placed in which Figures 1, 2

disclosed and without the under Fig. 2, and Fig. 3 at the right of Fig. 2, show as much of a complete system as is necessary for an understanding of the manner in which the system is organized and operates.

Referring to the drawings, the part of the complete system that is shown comprises a plurality of telephone lines extending from tus SC for governing the selection of an idle and appropriate operators position by an actuated cord selector.

The cord selector switches CS and CS are preferably of the type disclosed in Patent 1,177 ,044 to J. L. McQuarrie, issued March 28, 1916. Each switch comprises a. longitudinally movable shaft 1 carrying as many sets of brushes 2 as there are groups of stationary terminals to be engaged. To move the shaft and its sets of brushes up, an extension at the lower end of the shaft is brought into engagement with the constantly rotating power member 3 by means of an idler wheel operated by the-up-driv'e magnet 34; and to move the shaft down, the extension is brought into engagement with the power member 4 by means of an idler wheel operated by the down-drive magnet 35.

Normally the brushes of each of the sets 2 r are held apart so as to clear the associated terminals by means of a separating cam 5 located between the innermost brushes of the set. The cam 5 is rotatably mounted, and when rotated, releases the brushes and permits them to engage the associated terminals. The tripping or releasing of the brushesis controlled by a number of tripmagnets 20, 21. Each of these when energized rotates an associated trip rod 6 that extends transversely to the switch shafts 1 and carries as many tripping yokes 7 as there are finder switches in the group. The tri rod in rotating brings all of its trip-' ping yokes 7 into position to operate the brush controlling cams 5 of the corresponding sets of brushes on all of the switches, so that whichever of the selector switches is caused to move up, has that set of brushes tripped that corresponds with the particular trip magnets 20,21, that is at the time energized. When the selector switch that has been in use is returned to its normal position, any of the associated controlling cams 5 that has been tripped is engaged and rotated in a reverse direction to separate its switch springs again and thus render them inactive. Each 0 the cord selector switches has associated with it a commutator 8 which comprises a number of stationary commutator segments and a set of movable brushes carried at the top of the switch shaft 1 and cooperating wlth the stationary segments. This commutator serves to make and break a number of controlling circuits in the various stages of the upward movement of the switch shaft.

The switches LF and LF, by means of which the finder circuits are brought into connection with the calling lines, may be of the same type as the cord selector switches, in which case they are supplemented with controlling their-operation; or they may be any other convenient type of switch, such as plugs and spring jacks for establishing connection between the finder circuits and the lines.

For controlling the circuits of the organization there are employed a number of sequence switches which are .shown at different points and are designated 200, 300, 400 and 500, respectively. These sequence switches may be of the type disclosed in Patent 1,127,808 issued February 9, 1915, to Reynolds and Baldwin. Each consists'of an electromagnetically controlled motor or driving mechanism and a number of asso: ciated switch contacts. associated with each of the sequence switches 200 are designated 201 to 21.7 inclusive; those associated with each of the sequence switches 300 are designated 301 to 303 inclusive, those associated with each of the sequence switches .400 are designated 401 to 413 inclusive and those associated with each of the sequence switches 500 are designated 501 to 506 inclusive. To each of the contacts associated with the various sequence switch cams are applied certain numerals. These numerals in the case of the cams 201, 301 401 and 501 indicate the only positions of the associated sequence switch in which these particular contacts are open; the numerals applied to all'of the other contacts of each sequence switch indicate the only positions of the particular associated switch in which the associated contacts are closed.

The identification of the lines-with respect to the class or sort of service each is to receive is effected in the present instance by means of a commutator, a development of which is shown at 150 in Fig.1. This commutator may consist of a number of separate disks, 151 to 163 inclusive, assembled upon the same shaft in the definite relation to each other indicated in the development, and conparts and circuits suitable for v The switch contacts stantly rotated by means of suitable. power names? disks and the external circuits. The disks 152 to 160 inclusive are constantly connected with battery through the medium of the disk 151. The disks 161 and 163 are connected with ground through the medium of the disk 162. The disks 152 to 160 inclusive have various-and difi'ering combinationsof con ducting and insulating segments, the arrangement being such that the circuit in which each of these commutator disks is included is made and broken in a way that is different from that in which each of the other commutator disks makes and breaks its circuit. Commutator disk 152 interrupts 'its circuit once per revolution of the commutator; and each succeeding commutator disk, up to disk 160, introduces an additional interruption per revolution, so that in the case of disk 160 the corresponding circuit is interrupted nine times for each revolution of thecommutator.

The disks 161 and 163 serve to produce the pick-up impulses, which impulses cooperate .with the identifying impulses produced. by

disks 152 to 160 inclusive, in a manner hereinafter to be explained to control the operation of the identifying and segregating mechanism associated with the circuits over which the calling lines are extended. The pick-up No. 2 impulses, five per revolution of the commutator, are produced by disk 161, and the pick-up No. 1 impulse, one per Fig. 3 in association revolution of the commutator, is produced by disk 163. in order to simplify the following of the circuit connections the pick-up No. 1 disk 163 is shown diagrammatically in with the parts that it controls, and pick-up No. 2 disk 161 is shown in the same way in Fig. 2 of the drawing.

It will be noted that each of the identifying disks 158, ments arranged to coincide with the live insulating segments of disk' 161 that produces the pick-up No. 2 impulses, While the other six identifying disks 152 to 157 inclusive are so arranged that conducting segments of the disks coincide in location'with the insulating segments of the pick-up disk 161. This difference in the relative arrangement of the conducting and insulating segments of the disks is employed tocontrol the automatic segregation of the calls from the different classes of lines, as will be explained hereinafter.

The manner in which the system is organiz ed will best be presented in connection with a description of the mode of its operation.

It will be assumed that the subscriber at station B-initiates a call. The removal of the telephone receiver from its switchhook' closes a circuitthat includes both windings of the line relay 12', the resting contacts of cut-ofl' relay 11' and both limbs of the line.

The line relay 12' is energized, and in closing its contact causes one of the switches as vmechanically operated switches,

159 and 160 hasinsulating seg-.

LF and LF to become connected with the calling. line and extend its circuit to the associated finder circuit F or F. This result may be brought about either directly by energizing the driving mechanism of one or the other of the switches if these are or indirectly by displaying a signal'in response to which a distributing operator may insert a finder circuit plug in the spring-jack of the calling line if switches ofthat type are pre ferred.

Assuming that the circuit of the calling line has been extended to the finder circuit F in one of the manners described or in any other convenient and well-known way, and that the sequence switch 200 associatedwith the finder circuit has thereby been moved out of position 4 by the energization of its motor magnet, the apparatus proceeds to select an operators position and extend the circuit of the calling line to one of the connecting circuits with which the selected position is provided. When the sequence switch reaches position 5 in its movement out of position 4:, it closes a circuit that prepares the selection-controlling mechanism SC for cooper- 'ation with the cord selector switch in the immediately following stage of operation of the system.

When the sequence switch 200 reaches 'position 5, a circuit is closed. that extends ion closed. When relay 55 of the selection-controlling apparatus attracts its armature as a result of the closure of the above traced circuit, it grounds a conductor that has branches 81 extending to the apparatus associated with each of the operators positions. At each operators position there is a relay 92, the energization of which is effected'by the grounding of the associated branch conductor 81, subject, however, to the control of resting contacts of an associ- 'ated relay 91 and of contacts 303 (1) of an associated sequence switch 300. The relay 91 and the sequence switch 300 are in turn controlled by circuits that are responsive to the busy or idle condition of the associated position, as will hereinafter be explained. When the position is unengaged, both of the above mentioned contacts included in the energizing path for the relay 92 are closed.

en the position is engaged and not in condition to have a call extended to it, one or the other or both of these contacts are open. Therefore, when the relay 55 operates and applies a ground to all of the branch conductors 81, only such of the relays 92 will be energized as are associated with positions where the operator is free to attend to an extended call.

Each of the operators positions is represented in the selcction-controlling apparatus SC by a group of three relays 77 or 78, 93 and 94, and each also has an assocla-ted tr1p magnet, 20 for position 0 and 21 for position 0. The relay 77 or 78 of each group is under the direct control of the associated position relay 92, the relay 92 in operatmg closing in its front contact and armature a circuit that extends from battery by way of conductor 82 and through the winding of the group relay 77 or 78 to ground. Thus when relay 55 is operated as the result of the movement of a finder sequence switch 200 into position 5, it causes the operation of all of the group relays 77 or 78 that are associated with operators positions which are in condition to receive an extended call.

The movement of the finder sequence switch 200 out of position 6 depends upon the closure of a circuit that extends from battery through the left-hand winding of relay 30, sequence switch contact 209 (6) of the associated finder circuit, sequence switch contact 209 ('9 to 4) of finder circuit F, conductor 76, left-hand back contact and armature of relay 54, right-hand back contact and armature of relay 61 to ground. The closure of this circuit is therefore dependent upon the condition of the sequence switches of the associated finder circuits and of the relays 54 and 61 that form part of the selection-contr0lling mechanism SO. When the relays 54 and .61 are inert and the sequence switches of the other associated finder circuits are in any of their positions from 9 to 4 inclusive, that is, when the selection-controlling mechanism is not serving any other finder circuit, the circuit traced above is completed, and the relay 30 is energized. The relay 30 in operating closes a circuit that extends from battery through the motor magnet and cam 202 (6) of the sequence switch 200, right-hand front contact and armature ofrelay 30, and sequence switch contacts 208 (18 to 14) and (2 to 7) to ground. The closure of this circuit moves the sequence switch out of position 6.

When the sequence switch 200 reaches position 6%}, it closes a circuit that extends from battery through the winding of relay 54, switch spring and resting contact of that relay, left-hand back contact and armature of relay 61, conductor 73, and sequence switch contact 215 (6?; to 8) to ground. Relay 54 in operating locks itself up over a circuit that extends by way of the switch spring and left-hand armature of relay 54 and the right-hand back contact and armature of relay 61 to ground. At the same time, relay 54 opens at its left-hand armature and back contact the circuit of test conductor 76, thus rendering it impossible for any other finder contact and armature of relay 54, and' through the pick-up commutator disk 161 to round. Relay 68 in operating completes a ranch circuit to ground by way of the front contact and armature of relay 68, winding of relay 66, and right-hand back contact and armature of relay 61. This branch path, however, is temporarily shortcircuited by the direct path to ground by way of the pick-up commutator disk 161. But when the disk 161 in its rotation interrupts this path, the'removal of the short circuit from the branch path traced through the winding of relay 66 permits the lastmentioned relay to be energized and attract its armatures. In attracting its armatures the relay 66 opens at its outer armature and back contact the path over which the relay 68 was first energized, but leaves the relay 68 energized in series with relay 66 under the control of the right-hand back contact and armature of relay 61.

When relay 66 attracts its armatures, as above described, it closes a path over which the energization of the relay 65 is controlled. The relay 65 is the relay the operation or non-operation of which determines whether the call is to be directed to one or another of the operators or groups of operators. This controlling path for the relay 65 extends from battery through the windin of relay 65, the lower switch spring and ack contact of that relay, inner front contact and armature of relay 66, back contact and armature of relay 69, and back contact and armature of relay 67 to ground. As relay 67 is at this moment inert, and as relay 66 is energized, as already described, the energization or non-energization of the segregation-controlling relay 65. is dependent upon whether relay 69 is inert or energized. We are assuming that the call wh1ch is being extended is one initiated by the subscriber at station B. In this case, when the commutator 150 has reached that position in its rotation where one of the insulating segments of the disk 161 has just passed under the brush of the associated disk, the brush of the disk 155, which is associated with the lines of the class of which that exment with a conducting portlon of the disk.

. rotate, and an instant later the insulatingaaeaev Consequently a circuit is completed that extends from battery by way of brush 139 and disk 151, disk 155 and its associated brush, conductor 143, engaging contacts of the switch LF, conductor 51, sequence switch contact 217 (6%,? to 7), conductor 79, windmg of relay 69, back contact and armature of relay 67 to ground. Consequently the armature o the relay 69 is held attracted,

and the previously traced circuit that includes the winding of relay is held open thus preventing relay 65 from being energized. The commutator 150 continues to segment of pick-up No. 2 disk 161 has passed the associated brush 139 and permitted the pick-up circuit again to close. This closure of the pick-up circuit permits current to flow from battery, through the windings of relays 64 and 67 in parallel, lower switch spring and back contact of relafy 64, outer front contact and armature o relay 66, right-hand front contact and armature of relay 54, and commutator 161 to ground. Relay 64in operating closes at its switch spring and lower armature a locking circuit for itself and relay 67 which extends to ground by way of the right-hand back contact and armature of relay 61. At its upper armature and front contact, the relay 64 closes a circuit that permits an ener izing impulse to flow to the selection-controlTing a paratus of an idle one of the positions in the group that has been selected, in a manner which will be described later. The relay 67 in operating opens the path to ground of the circuits over which the relays 65 and 69 are controlled, so that the commutator 150 can have no further control over the selectioncontrolling apparatus.

If it be assumed that the call that is being extended was originated by the subscriber at station A, then the relay 69 is permitted to fall baclcwhile the circuit of the pick-up No. 2 disk 161 is open, and consequently relay 65 is energized. This action is brought about by the circumstance that the identifying conductor 52 of the line extending to station A is connected with an identifying disk 158 which has insulating segments arranged to coincide in location with the insulating segments of the pick-up No. 2 disk 161. Thus, while the relay 66 is ener ized' as a result ofthe first interruption o the pick-up No. 2 circuit, as prevlously described, the circuit extending from battery through the identifying disk 158 is interrupted. Therefore, there is an interuption of the path extending by way of the identlfying conductor 52 of the station A line, engaging contacts of the switch LF, sequence switch contacts 217 (6% to 7), conductor 79, winding of relay 69, and back contact and armature of relay 67 to ground. As a re-' sult, relay 69 releases its armature and 'pick-upNo. 2 im finder circuit obtains accessoto the selectioncloses the previously-traced circuit that extends from battery through the winding of relay 65, switch s ring and back contact of that relay, inner ront contact and armature of relay 66, back contact and armature of re- 69, and back contact and armature of re ay 67 to ground. Relay 65 in operating closes a locking circuit for itself that extends by way 01 its switch spring and lower armature, and the right-hand back contact and armature of relay 6,1 to ground. Thus" in the case of a call originatln at station A, the relay 65 is energized anc held operated, so that when an instant later (at the moment the succeeding pick-up No. 2 impulse starts to flow) relay 64 is operated the energizing impulse for the operation 011 the selection-controlling apparatus is directed over conductor 141 to a different operators position or group of positions.

' To re-state the matter briefly, the first pulse that flows after the controlling apparatus The cessation of the first pick-up impulse operates the relay 66 and prepares a path for the energizatlon of the segregation-controlling relay 65, subject, however, to the control of the relay 69. The control of the relay 69 over the relay 65 lasts only until the succeeding pick-up No. 2 impulse starts, at which time the controlling circuit is broken by the operation of'the relay 67. If during this interval the relay 69 becomes inert, as a result of an insulating segment of the identifying disk of the calling line being disposed so as to coincide with one of the insulating segments of the pick-up No. 2 disk 161, then the segregation-controllin relay 65 is operated to direct the selecting impulse over conductor 141 to a certain operators position or group of positions. But if the relay 69 is held energized, as a result f the identifying disk of the calling line having conducting segments disposed so as to coincide with insulating segments of the pick-up No.

2 disk, then the segregation controlling relay 65 is not operated, and the selecting impulse is directed over conductor 142 to another operators position or group of positions.

It is customary to provide each of the cord selector switches CS and CS with twenty sets of brushes 2 and to associate with each set the terminals of twenty-five connecting cord circuits. In their normal condition the sets of brushes are held out of engagement with the connecting cord circuit terminals as the switch moves up; but the brushes of any set may be made active to engage the associated terminals by a momentary actuation of the corresponding trip magnet 20, 21, etc., as the switch starts on its upward movement. Consequently a call that has reached a finer circuit may be directed to operates the relay 68.

I gization of-the corresp any one of the twenty operators positions by the selective actuation of the corresponding trip magnet to trip the correspondmg' set of brushes.

This selective actuation of the tri mag- 8) in the series of K081610118 associated with the path chosen. may extend serially through the contacts of a number of relays 78, of which two are shown each bein associated with the select= ing apparatus 0 a corresponding operators posit1on. The path 141 may extend serially through the contacts of a number of relays 77, of which one only is shown, and may then, if desired, be carried serially through other contacts of the same relays 78 to which the path 142 is extended. The path 142, therefore, is operatively extended only to the positlons with which the relays 78 are associated; while the path 141, in case all of its first choice positions having the relays 77 are unavailable, is operatively extended to, the positions having the relays 78. In this way the flat rate calls may overflow into the message rate and coin collector ositions; but the message rate and coin co lector calls are confined to those positions which are provided with the special apparatus required to handle them. However it desired the path 141 may be confined to its own particular positions by carrying it thriough the series contacts of the relays. 77 on y.

The stage of the operation that has been reached in the foregoing description is that in which the sequence switch of the finder circuit F has reached position 7, and in which the relay 64 has operated to close whichever of the two paths 141 and 142 has been selected by the operation or non-operation of the relay 65. It is assumed in the paresent instance that the call is from station or from some station the identifying condu'ctor 52 of whose line is connected with one of the commutator disks 152 to 157 inclusive, and that relay 65 has therefore not been energized. As a result a circuit is closed that extends from battery through the lefthand armature and back contact of the relay 95 associated with the first operators position in the series associated with path 142 that happens at the time to be available (assumed in the present case to be the relay 95 at position 0), conductor 83, back contact and left-hand switch spring of the corresponding relay 93 of the selection-control- 1mg apparatus, winding of that relay, winding of the associated relay 94, right-hand switch spring and resting contact of relay onding relay 77 or.

s. shown, the path 142 93, frontcontact and armature of the associated rela 7 8, conductor 142, upper back contact an armature of relay 65, upper armature and front contact of relay 64, back contact and armature of rela 63, left-hand back contact and armature o relay 61,-conductor 73, and finder sequence switch contact 215 (6% to 8) to ground. The closure of this circuit energizes relays 93 and 94, and relay 93, in operating, disconnects the windings of both relays 93 and 94 from the initial energizing path by way of the front-contact of the amociated relay 78 and the back contact of the operators position relay 95, and includes them instead in a circuit that extends from battery by way of the winding of the rela 95, conductor 84, left-hand armature an switch spring of relay 93, thence through the windings o 94, the right-hand switch spring and armature of relay 93, and to groun by way of the path already traced through the lefthand back contact and armature of relay 61 and conductor 73. The closure of this path maintains the energization of relays 93 and 94 independent of control by relay 78, and also causes the ener 'zation of the relay 95 of the selected posit1on. Relay 94, in operboth relays 93 and at-ing, closes in its right-hand front contact I and armature of relay 63, left-hand back contact and armature of relay 61 and toground by wayof conductor 73 and sequence switch contact 215 (6% to 8). Relay 30, in

This relay,

operating, closes a circuit that extends from battery through the motor magnet and cam 202 (7) of the finder se uence switch, righthand front contact an armature of relay 30 and sequence switch contacts 208 (18 to 14) and (2 to 7) to ground.

The closure of the above clrcuit moves the I sequence switch 200 from position 7 to position 8.- In position 8, a circuitis closed that extends from battery through the up-drive magnet 34 of the associated cord selector switch GS, conductor 89, sequence switch contact207 (8 to 9), right-hand front contact and armature of rela switch contact 215 (8 to 9) to ground. The relay 30 is at this time held energized as a result of a locking circuit by way of its right-hand winding that was completed 30, and sequence when the relay was operated in position 7 of the sequence switch by the actuation of relay 63 of the selection-controllin a paratus, as previously described. This Too 'ng circuit extends from battery through sequence switch contacts 205 (2 to 9), right-hand I winding of relay 30, se uence switch contacts 216 (7 to 9) and 2 to 9), left-hand front contact and armature of relay 30, and to ground by way of the armature and back contact of relay 37. The up-drive magnet 34 remains energized and the upward movement of the cord selector GS continues as long as the relay remains energized; and the continued energization of the relay 30 is under the control of relay 37 which governs the locking circuit of relay 30. I

At the outset of the upward movement of the cord selector CS, the tripping levers 5 of all of the sets of brushes come into position to be engaged by their corresponding tripping yokes 7 and as it is the trip magnet 21 that in the present instance is energized, that set of brushes 2 is tripped and made active which is adapted to engage the terminals of connecting circuits leading to the corresponding operators position 0.

It also opens,

Immediately after the brushetripping point is passed, a circuit is closed that releases the selection-controlling apparatus and moves the finder. circuit sequence switch into its next position. This circuit extends from battery throu h the winding of relay 61, conductor 4, sequence switch contact 211 (7% to 8), conductor 80 and segment K of the cord selector commutator and corresponding brush to ground. In operating, the relay 61 closes a locking circuit for itself by way of its left-hand front contact and armature, conductor 73 and sequence switch contact 215 (6% to 8) to ground. in its left-hand armature and back contact, the connection of the conductor 73 with the operated group relays 93 and 94 and the position relay 95 of the 0 opera tors position, which connection up to this time had been maintaing these relays energized. The above mentioned relays therefore become inert, deenergize the associated trip magnet 21, andrestore these circuits of the selection-controlling apparatus to their normal condition. The relay 61, in operating also opens, at its right-hand armature and back contact, the common locking circuit of the relays 54, 66, 68, 64, and 67 of the segregation-controlling group. These relays thereupon release their armatures and are in readiness to cooperatein the extension of another calling line. Finally, the relay 61 in operating, also closes a circuit that extends from battery through the motor magnet and cam 204 (8) of the finder circuit sequence switch, conductor 75, and right-hand front contact and armature of relay 61 to ground. The closure of this circuit moves the finder circuit sequence switch from position 8 to position 9. As it moves out of position 8, the finder'sequence switch opens the locking circuit of relay v6l, and, in reaching position 9,'closes in sequence switch contact 209 (9 to 4) the series path which is employed for moving out of position 6 the sequence switch of any of the finder circuits. As ground has been reapplied to this series path by way of conductor 7 6 and resting contacts of relays 54 and 61 inthe release of the last mentioned relay at the completion of the selecting operation, the selection-controlling apparatus SC is again available for the use of any finder circuit that is ready to extend a call.

If the assumption were that the call is from station A, or from some station the identifying conductor 52 of whose line is connected with one of the commutator disks 158, 159 and 160, then the operation of the selection-controlling apparatus would have been the same as that which has been described excepting that the relay 65 being energized, an idle one of these positions with which the path 141 is associated would have been chosen and its trip magnet 20 operated.

After the cord selector switch CS passes the brush-tripping position, it continues its upward movement until the brushes are stopped by engaging the terminals of one of the connecting circuits that is idle or un-' engaged. The idle or busy condition of the connectin circuit is indicated by the presence or a sence of ground on the test terminal 118 of each connecting circuit. When the brushes engage the terminals of an idle connecting circuit, a path for the fiow of current is completed from battery through the windings of the relay 37, sequence switch contact 206 (8 to 9), conductor 99, brush 114, test terminal 118,conduct0r 88, listening key sequence switch contact 406 (1) and backcontact and armature of relay 420 to ground. Relay 37 thereupon attracts its armature and opens the previously traced locking circuit that has been holding relay 30 energized. Relay 30, in releasing its armatures, opens in its right-hand front contact and armature, the energizing circuit for'the up-drive magnet 34, thus stopping the brushes of the cord selector switch in engagement with the terminals of the selected connecting circuit. In engaging its back contact, the right-hand armature of relay 30 closes'an energizing circuit for the motor magnet of the finder sequence switch, by way ofcam 202 (9) and cam 215 (8 to 9), which moves thesequence switch 200 out of position 9.. The finder sequenceswitch then switch leaves position 9, it closes a circuit that extends from battery through the wind ing of relay 421 of the connecting circuit, listenin key sequence switch contacts 407 (1), le -hand back contact and armature of relay 422, conductor 87, cord selector switch terminal 117 and corresponding brush 113, conductor 98, and finder sequence switch contacts 205 (9% to 14) and (9% to 11) to ground. Relay 421, in operating, closes a locking circuit for itself that extends by way of its left-hand front contact and armature, and sequence switch contact 405 (1 to 6) to ground. Relay 421 also closesa circuit that extends from battery through the motor magnet and cam 403 (1) of the listening key sequence switch and right-hand front contact and armature of relay 421 to ground. The closure of this circuit causes the listening key sequence switch to move out of position 1, and in doing so, to open the test conductor 88 in sequence switch contact 406 (1), thus making the connecting circuit test busy, and also to open in sequence switch contacts 407 (1) the path over which the relay 421 was first energized.

Associated with relay 421 is a relay 423 which is energized and locked up over the same path as relay 421. Relay 423, in operating, closes a circuit that extends from battery through the winding of relay 422 and front contact and armature of relay 423 to ground. As a result, relay 422, prior 'to the moving of listening key sequence switch out of position 1, has disconnectedconductor 87 from connection with battery by way of sequence switch contact 407 (1) and the windings of relays 421 and 423,

and has connected it with an alternative path to battery by way of the left-hand front contact of relay 422 and the device 424. When the listening key sequence switch reaches position 2, an additional path to ground for holding the relay 422 energized is closed by way of sequence switch contact the listening key sequence switch interrupt the talking strands of the connecting circuit and include between their severed ends a loop that has connection by way of conductors 135 and 136 with the operators telephone set 147. This puts the operator in communication with the calling subscriber.

In position 7, the cams 405, 406 and 413 also close the circuits that they control. The circuit closed by the cam 413- includes the commutator disk 163 of pick-up No. 1. This disk closes its circuit for an instant once for each revolution of the commutator. Upon the first -of these closures that follows the movement of the sequence switch 400 into position 7, a circuit is closed that extends from battery, through the winding of the relay 442, back contact and armature ofrelay 440, back contact and armature of relay 441, sequence switch contacts 413 (7 and pick-up No. 1 commutator 163 to ground. Relay 442 in operating closes a branch to ground of the above-traced circuit that extends by way of the left-hand front contact and armature of relay 442, winding of relay 441, and sequence switch contact 405 (6 to 7). During the interval that the pick-up No. 1 commutator 163 keeps its branch to ground closed, the winding of the relay 441 in the other branch is shortcircuited. But when in the rotation of the commutator the branch by way of the picku disk 163 opens, the removal of the short circuit from the winding of relay 441 causes that relay to attract its armature. This disconnects the pick-up No. 1 commutator 163 from the previously traced path including the winding of the relay 442, and connects it with the winding of the relay 444 by'way of the ri lit-hand back contact and switch spring 0 that relay. Therefore, the relay 444 is in. condition to be energized when the pick-up No. 1 commutator again closes its circuit upon the completion of one revolution of the commutator. During this interval, the relays 441 and 442 are both maintained energized by being included in series in the circuit that is closed to ground by way of sequence switch contact 405 (6 to 7).

The operation of relay 442 closes a circuit that includes the relay 443 in circuit with the path over which the identifying impulses applied to the calling line are caused to flow. As the calling line in the present case is assumed to be the line extending from station B, the circuit that is closed is as follows: from battery, through commutator disk 151, commutator disk 155, conductor 143, conductor 52, corresponding line terminal and brush of the finder switch LF,

conductor 51, sequence switch contact 207 p (14), right-hand front contact and armature of relay 30, sequence switch contacts 208 (18 to 14) and (14), conductor 99, cord selector brush 114, cord selector terminal time the pick-up No. 1 impulses is trans-.

mitted by disk 163, the disk 155 associated with the line that is assumed to be calling has a conducting segment beneath its brush. Consequently, the identifying circuit traced aaeaoer *above\ is completed the moment relay 442 'closes a locking circuit for itself that extends by way of its right-hand front contact and armature, conductor 139, and seswitch closedbetween positions, and open quence switch contact 405 (6 to 7) to ground. The relay 445 therefore continues energized as long as the listening key sequence switch 400 is in position 7. Relay 445 in operating also prepares a circuit for the operation of relay 446, this circuit eX- tending from battery, through the winding of relay 446, and left-hand front contact and armature of relay 445 to the back contact of relay 443, where the circuit remains open until relay 443is deinergized. The last-mentioned relay is denergized as soon as the identifying commutator 150 has rotated "far enough tobring the first of the series of insulating segments beneath the associated brush 139. When this occurs, the relay 443 releases'its armature and completes to ground, by way of the left-hand back contact and armature of relay 444, the circuit including the relay 446. Thereupon relay 446 operates, and in doing so, closes a locking circuit for itself by way of its lett-hand front contact and armature and the sequence switch contact 502 to ground.

This particular cam of the sequence switch 500, as is indicated, is so arranged as to be closed in all of the resting positions of the sequence switch, and to be opened between positions. In its normal condition, the serelay 446 in operating closes a circuit that extends. from battery, through the motormagnet and contact 503 (1 to 18) of sequence switch 500, and the right-hand front contact and armature of relay 446 to ground. As a result, the sequence switch 500 is moved out of position 1, thus breaking the locking circuit of the relay 446, which relay thereupon releases. switch 500 is so arranged as to keep the energizing circuit of the motor magnet of that at each of the'eighteen positions in which ferring to the sequence switch cam 505 controlling the circuits of the lamps 451, 452

The cam 501 of sequence the switch is adapted to rest. The effect, I therefore of the passingof the first insulating segment of the disk 155 beneath its brush is to advance the sequence switch from position 1 to position 2.

As each of the remaining three insulating segments of the four with which the identifying disk 155 is provided passes beneath the associated brush, the relay 443 releases its armature and causes a pulse of current to pass through the winding of relay 446, and each pulse of current that passes causes the relay 446 to advance the sequence switch 500 to t e next succeeding position and to lock up the relay 446 unt1l the sequence switch has completed this next step. Therefore, when the last of the four insulating segments of disk 158 has passed beneath the associated brush, the sequence switch 500 is resting in position 5. When the commutator 150 completes its cycle of rotation and again brings the conducting segment of ick-up No. 1 disk 163 beneath its associated rush, a circuit is completed that extends from battery, through the winding of relay 1 444, right-hand switch spring and back contact ofthat relay, front contact and armature of relay 441, sequence switch contacts 413 (7), and pick-up No. 1 commutator disk 163 to ground. Relay 444 in operating at completes a lockin circuit for itself that extends by way oi 'its right-hand switch spring and armature, conductor 139, and sequence switch contact. 405 (6 to 7) to ground. -The operation of the relay 444 opens at the right-hand armature and back contact of that relay the circuit over which, up to this time, the identifying impulses have passed to the relay 443, and keeps this circuit open thereafter until the listening key sequence switch moves out of position 7. The relay 444 also opens at its left-hand armature and back contact the path to ground over which the relay 443 has efl ected the energization of the relay 446, and at the same time closes a circuit for the illumination of whichever of the six lamps 451 to 456 inclusive have been placed in readiness "for illumination by the operation of the se-. quence switch 500.

Under the conditions assumedin the present case, the association of the identifying disk 155 with the calling line has caused the sequence witch 500 to move to position 5 and come to rest in that position. By reand 453 in one sub-group, and the sequence switch cam 504 controlling the circuits of the lamps 454, 455 and 456 in the other subgroup, it will be seen that in position 5 of the sequence switch, the circuit of lamp 451 of the first sub-group, and the circuit of lamp 455 of the' second sub-group, are ex tended to the left-hand front contact and 130 armature of relay 444. Consequently, when the passa e of the second pick-up No.1 1mpulse at tie end of the cycle of rptat on of the commutator causes the .energlzation of the relay 444, the two lamps 451 and 455 are lighted. The lamps 451, 452 and 453, respectively, identify the calling line as an individual line, a arty line, or a prlvate branch exchange l1ne.; and the lamps 454, 455 and 456, respectively, identify the calling line as a fiat rate line, a message rate line, or a coin box line. Consequently, the illumination of the lamps 451 and 455 1ndicates to the operator that in the present instance, the line that is calling is an individual message rate line.

Obviously the lamps of the two sub-groups may be lighted in nine combinations of two lamps, one lamp in each of the sub-groups at a time; and the sequence switch 500 is so arranged that in each of the nine os1tions in which it mayrest, from position 2 to position 10 inclusive, 9. different combination of the lamps, two at a time, will be displayed. It is therefore possible, by connecting the identifying conductor of each of the lines of the exchange with one or another of the nine identif ing disks of the commutator 150, .to provi e for the identification of nine classes of lines with respect to the character of the line and the sort of service to be received. Of course, any classification that is desired may be adopted. In the present instance, the individual coin box lines are identified by disk 152 of the com mutator, and cause the display of the lamps 451 and 456. The party coin box lines are identified by disk 153, and cause the lighting of lamps 452 and 456. PBX coin box lines, if there are any such are identified by disk 154, and cause the lighting of lamps 453 and 456. Individual message rate lines are identified by disk 155, and cause the lightin of lamps 451 and 455. Party message rate ines are identified by disk 156, and cause the lighting of lamps 452 and 455. PBX message rate lines are identified by disk 157 and cause the lighting of lamps 453 and 455. Individual flat rate lines are identified by disk 158, and cause the lighting of lamps 451 and 454. Party flat rate lines are identified by disk 159, and cause the lighting of lamps 452 and 454. PBX flat rate lines are identified by disk 160, and cause the lighting of lamps 453 and 454.

The identification of the sort of line that is calling is automatically effected, in the manner described above, as soon as the listening key sequence switch 400 has moved into position 7. The movement of this sequence switch into position 7 has also, as hereinbeforedescribed, connected the operatorstelephone set 147 with the connecting cord circuit to which the circuit of the calling line has been extended. The operator, being informed of the character of the line that is calling, communicates with the calling subscriber and, upon learning the number of the line that is wanted, she may complete the connection by inserting the calling plug 425, in which in the present instance the connecting circuit is represented as terminating, into the springjack 14 of the called subscribcrs line. Instead of a plug and spring-jack, any other of the well known witching devices or mechanisms for establishing connection between a connecting circuit and a-tclephone line may obvious y be employed. In the present instance, the connectlon-exten'ding means is represented as a cord circuit provided with a repeating coil 426, answering and calling supervisory relays 427 and 428, respectively, and a switch 429 for applying ringing current from the source 430 to ring the bell at the called ubscribers station D. As all of these parts may have their usual functions and may operate in the usual way, a description of them and of the exact manner in which the cord circuit is organized is thought to be unnecessary.

When the calling plug 425 is inserted in the called line spring-jack, an energizing circuit is completed that includes serially the winding of the connecting cord relays 420 and 431 and the cut-off relay 11 of the called line. The cut-oft relay 11 ma have its usual functions of disconnecting tie line relay 12 thus depriving the line of control over the calling apparatus. The relay 420, in operating, interrupts, at another point the path to ground of the test conductor 88. The relay 431, in its back contact, breaks the connection of the tip of the plug with a conductor 133, which may extend to the operators telephone apparatus and be used in connection with testing the called line be fore inserting the plug, and, in its front contact, closes the tip strand of the connecting circuit for talking purposes.

After the connection between the calling line and the called line has been established, the operator may disconnect her telephone apparatus from the connecting circuit b pressing the key 432. This closes a circuit that extends from battery through the motor magnet and cam 402 (7) of the listening key sequence switch 400, and to ground by way of the closed contact of the key 432. The switch 433 is closed when the calling plug 425 is inserted, so that when the listening key sequence switch moves out of position 7 as a result of pressing key 432, the energization of relay 422 is maintained by a path that extends through the right-hand front contact and armature of the relay and to ground by way of the closed contacts of switch 433.

The movement of the listening key seteac er quence switch 400 out of position 7 also interrupts the circuits that are controlled in the contacts 405 (6 to 7), 406 (7) and 413 7). The openin of the contact 406 (7) isconnects the i clentifying conductor 88 from the path which extends to the relay 443 of the common identifying apparatus. The opening of sequence switch contacts 413 (7) disconnects the pick-up No. 1 commutator 163. The breaking of sequence switch contact 405 (6 to 7) removes ground from the conductor 139, and consequently unlocks the relays 441,442, 444 and 445 of the common identifying apparatus, and permits them to return to their normalcondition in readiness to control the identification of another calling line. The relay 444 in releasing its armatures opens the enerizing path for whichever pair of lamps has been lighted and brings about the extinguishment of these lam s. The releasing of the armatures of the relliys 444 and 445 also closes a circuit that extends from battery, through the motor magnet and contacts 503 (2 to 18) of the sequence switch 500, lefthand back contact and armature of relay 445, back contact and armature of relay 443, left-hand back contact and armature of relay 444 to ground. The closure of this circuit energizes the motor magnet of the sequence switch in any position to which it may have been advanced, and causes the switch to return to position 1, in which the energizing circuit is interrupted and the switch comes to rest.

Provision is made for preventing another-train of identifying impulses from reachin the class of service responsive devices while the sequence switch 500 is re turning to its normal position. This is efiected through the medium of the relay 440 and its associated circuits and mechanism. it while the sequence switch 500 is returning the listening; key sequence switch 400 of another one of the operatorfs cord circuits is moved into the listenin position, a circuit is closed that extends 'rom battery through the winding of relay 440, sequence switch contacts 506 (2 to 184;), right-hand back contact and armature of relay 445, conductor 139, and to ground by way of listening key sequence switch contact 405 (6 to 7). Relay 440 thereupon completes at its left-hand front contact and armature, a. locking circuit for itself, and at its righthand back contact and armature opens the previously-described path over which relay 442 is initially energized by the impulse from pick-up No. 1 commutator 163. Conseque'ntly relay 442 is prevented from closing the path over which the identifying impulses flow to the relay 443. An instant before the sequence switch 500 arrives at position 1, it opens at its contacts 506 (2 to Before the connection is released, however, a charge is made by depressing key 435. This act disconnects conductor 87 from. battery by way of device 424, and completes a circuit that extends from a higher potential battery 438, by way of low resistance relay 436, lever and switch spring of key 435, left-hand front contact and armature of relay 422, conductor 87, contact 117 and brush 113 of the cord selector switch, conductor 98, finder sequence switch contacts 205 (9%; to 14) and (12 to 14), righthand Windin of relay 30, sequence switch contact 212 512% to 14), corresponding contacts of switch Lit, conductor 53 of the station B line, and to ground by way of the winding of message register 13. In operating, the register 13 ShOI'tsCll'CllltS one of its windings, which so increases the current flow in the path just traced that the low resistance rela 436 is operated and lights the associate lamp 437, which informs the operator that the charge has been registered.

Or in case the class-of-service signals have indicated to the operator that the calling line is a coin-box line, she may collect the coin before releasing the connection by pressing key 447. This applies to the tip conductor of the calling subscribers line,

current from the high potentialsource 449 by way of the winding of relay 448; and that relay in operating lights the associated lamp 450 to notify the operator that the current has been applied. The operator is also supplied with means forreturning the coin in case the connection has not been successfully extended. Such means is well known in the art, and need not be described.

Disconnection is effected by opening switch 433. This interrupts the energizing circuit of relay 422, and that relay, in releasing its armature breaks the connection of conductor 87 with battery by way of the device 424. When current ceases to flow through conductor 87, the relay 30 of the finder circuit, which has been included in the path of current flow by way of conductors 87, 98, 50 and 53 and finder sequence switch cams 205 and 212, releases its armatures; This closes a circuit from battery through motor mag net and cam 202 (8 to'14) of the finder sequence switch, left-hand back contact and armature of relay 30 and armature and back contact of relay 37 to ground. This moves the finder circuit sequence switch from. posi tion 14 to position 15, where a circuit is closed from battery through the motor ma nct and cam 202 (15) of sequence switc h 200, right-hand back contact and armature of relay 30, andcaln- 215 (15) to ground. When the finder sequence switch reaches position 16 as the result ofthe closure of the above circuit, a circuit is completed that directly or indirectly may cause the brushes of the switch LE to be disconnected from the terminals of the calling line and restoring the switch LF to its normal position in a manner clearly disclosed in the patent of S. B. Williams, J r. Serial No. 107,090 filed July 1, 1916. When this disconnection is eflect'ed, a circuit may be completed that extends from battery through the motor magnet and cam 204 (16) of the finder sequence switch to ground. This moves the finder sequence switch 200 to position 17, in which position a circuit is closed that extends from battery through the down-drive magnet 35 of the cord selector switch CS, conductor 90 and finder sequence switch contact 215 (17) to ground. This causes the return of the cord selector switch. "When the switch reaches its normal position, it closes a circuit that extends from battery through the motor magnet and cam 204. (17) of the finder sequence switch, conductor 31 and segment Y of the cord selector commutator and corresponding brush to ground.- This causes the return of the finder sequence switch 200 to its normal or 1 position; and from this position it is later moved through its 1, 2 and 3 positions by means of circuits controlled in finder sequence switch cams 202 and 203 as is more fully disclosed in the above named patent to S. B. Williams, Jr. These circuits are not concerned with the present invention and v need not be described.

When the switch 433 is opened to release the connection a switch 434 is operated to complete a circuit that extends from batter through the motor magnet and cam 402 (15) of the listening key sequence switch and closed contacts of switch 134 to ground. The closure of this circuit moves the listening key sequence switch from its listening out position 15 to its normal position 1. This restores the. connecting circuit to its normal condition and renders it again available for selection by a cord selector.

As has been explained hereinbefore, the selection controlling apparatus SC includes a relay 77 or 78 for each ofthe operators positions to which the selection-controlling apparatus is adapted to cause the cord selector switches to extend calls; and unless the corresponding relay 77 is energized, a cord selector that is extending a call cannot select that operators position. The energization .of relay 77 'is under the control of the associated relay 92 at the corresponding operators position; and the energization of the relay 92, by the operation of the common; relay 55 when a selector switch is ready to extend the call, is in turn under the control of switches that are responsive to the engaged or unengaged condition of the corresponding operators position. The above mentioned switches, in the present instance, are the cam 303 of the operators sequence switch 300 and the armature and resting contact of the relay 91. One or the other or both of these switches is operated to open the energizing path of the relay 92 whenever the operators position is unavailable for receiving, calls.

Thus, when the operators position has been selected by one of the call extending circuits, the position is rendered inaccessible to other call extending means. When the position is selected, the relay 95 is operated in a mannerpreviously described. In operating, the relay 95 closes a circuit that extends from battery through the motor magnet and cam 302 (1) of the operators sequence switch, right-hand front contact and armature of relay 95, and right-hand front contact and armature of relay 125 to round, The relay 125 at this time is operate as its energizing path is completed by way of local contacts 127 of the operators telephone jack phone plug inserted in the telephone jack.

As a result of the closure of the circuit traced above, the operators sequence switch 300 is moved out of position 1, thus opening the energizing path of relay 92 in sequence switch contact 303 (1) and making the position unselectable.

The nextresting position of the operators telephone sequence switch 300 is position 4; but as relay 125 is energized, the motor magnet has an energizing circuit in this position by way of sequence switch contact 302 (4) and the left-hand front contact and armature of relay 125 to ground, and consequently the sequence swltch moves on to its next resting position 17. The sequence switch remains in position 17, keeping the operators position unselectable, until at a later stage in the operation, the switch 192 is operated in any suitable manner, to closemeans? a ing key se aence switch 400 of any of the connecting circuits of the 0 erators position is moved to position 7 to brlng the operators telephone set into connection with the corresponding circuit, an energizing path is' completed thatextends from battery through the-winding of relay 91, conductor'l37, and listening key sequence switch contact 40a (2 to 9) to ground. The completion of this circuit causes the relay 91 to attract its armature and interrupt the path over which relay 92 is adapted to be energized, thus preventing the operation of the associated selection-controlling relay 77 or 78.

The removal of the telephone plug from the operators telephone jack 126 when the operator leaves her position, also renders the position unselectable. When the plug is removed, the breaking of the local contact 127 causes relay 125' to become inert and release its armatures. This closes a circuit that extends from battery through the motor magnet and cam 802 "(1) of the operators telephone sequence switch 300, and to ground by way of the left-hand back contact and armature of relay 125. In moving out of position 1 as the result of the closure of this circuit, the sequence switch interrupts the energizing-path for the relay 92 in sequence switch contact 303 (1), thus pre venting the operation of the corresponding selection-controlling relay 7:? when a connection is to be extended.

Tn order that the features to which this invention is directed may be fully and clearly disclosed, it has been necessary to describe them in connection with other tea tures that are the subject of copendlng applications assigned to the same assignee, such applications includin the applications of S. B. Williams Jr., erial No. 29,875, filed May 22, 1915, serial NO. 107,090, filed July 1, 1916, and application of Franklin A. Steam, Serial No. 107,540, filed July 5, 1916. Such other features are the subject of claims in the applications'mentioned above and are. not claimed in the present application.

What is claimed is:

1. In a telephone system, the combination with a plurality of lines adapted to receive difi'ering sorts of service, of identifying means associated with each of the lines of a given sort, a plurality of operators positions, means for extending said lines to said positions, and mechanism selectively responsive to said identifying means for extending calls from the corresponding lines toa particular operators position;

2. The combination with a plurality of lines adapted for difierent kinds of service, said lines being intermingled irrespective of line groups of a plurality of connecting circuits, means for extending said lines to said circuits, andmeans for automatically segregating to certain of said circuits the calls sponding kinds of service, and means made operative b any of said lines in calling for extending the circuit of the line to an operators position adapted to give the service which the calling line is intended to receive.

4. The combination with a plurality of lines adapted, to receive differing kinds of service, means associated with each line for identifying the same with respect to the kind of service it isadapted to receive, a plurality of operators positions, means responsive to said identifying means for distributing calls from said lines among the operators positions in accordance with the kind of service to be received, and a responsive device at one of said operators positions for indicating the kind of service for which a calling line extended to said position is adapted, said responsive device being controlled by the aforesaid identifying means.

5. The combination with a lurality of operators positions, of a plurality of call-extending circuits each having access to all of said operators positions, a plurality of lines adapted to receive diflering kinds of service and served by said call-extending circuits,

selective mechanism for-controlling the se- "with said lines for identifying the same with respect to the .kind of service which each is to receive,-and mechanism selectively responsive to the identifying means of the various lines for controlling the extension of a calling line to an operators position adapted to give a corresponding sort of service.

7. The combination with aplurality of lines adapted to receive differing kinds of service and a plurality of operators positions adapted to give corresponding diflering kinds of service, of means for automatically distributing the calls originated by said lines among said operators positions in accordance w1th the kinds of service said lines and positions are adapted to receive and give.

llti

8. The combination with a pluralit of lines adapted to receive different kin s of service and a plurality of operators positions adapted to give corresponding diifering kinds of service, of means for automatically distributing the calls originated by said lines among sald positions in accordance with the kinds of service said lines and positions' are adapted to receive and give, and mechanism at one of said operators positlons for automatically indicating the kind of service a calling line is adapted to recelve.

9. The combination with a plurality of operators positions, of a plurality of lines having access thereto, said lines being adapted to receive diiferin kinds of service, of means for automatiea ly directing the calls from those lines adapted for certain kinds of service to one of said operators positions, and means associated with said position for indicating the class of service which a calling line is adapted to receive.

10. The combination with a operators positions adapted to give differing kinds of service, of call-extending circuits each having access to all of said operators positions, a plurality of lines adapted to receive differing kinds of service and served by said call extending circuits, means for applying to each call-extending circuit characteristic trains of impulses, each train corresponding with the kind of service which a line temporarily served by a call-extending circuit is adapted to receive, and mechanism selectively responsive to said various characteristic trains of impulses for controlling the selection by the call-extending circuit of an appropriate operators position.

11. The combination with a plurality of operators positions adapted to glve differing kinds of service, of call-extending circuits each having access to all of said operators positions, a pluralit of lines adapted to receive differing kin s of service and served by said call-extending circuits, means for applying to each call-extending circuit characteristic trains of impulses, each train corresponding with the kind of service which a line temporarily served by a call-extending circuit is-adapted to receive, mechanism selectively responsive to said various characteristic trains of impulses for controlling the selection by the call-extending circuit of an appropriate operators position, and signal' mechanism at certain of said operators positions also selectlvely responsive to said characteristic trains of impulses for indicating the kind of service an extended calling line is to receive.

12. The combination with a pluralit of lines adapted to receive differing kind: of service, of a plurality of operators ositionscall-extending circuits for exten ing said lines to said operators positions, means for producing upon a call-extending circuit a plurality of characteristic electrical condition corresponding with the kind of service the line temporarily associated with said call extendmg circuit is adapted to receive, selective mechanism selectively responsive to the different characteristic electrical conditions for ex-. tending'each call-extending circuit to a particular operators position, and signaling means at certain of said operators positions also selectively responsive to said variou characteristic conditions.

13. The combination with a plurality of lines adapted to receive dififering kinds of service, a plurality of operators positions adapted to give corresponding differing kinds of service, means for producing a plurality of characteristic trams of electrical impulses, the impulses of one train differing from the impulses of another train in the number and the timing of the impulses, mechanism selectively responsive to the timing of the impulses of the trains for controlling the extension of each calling line to a particular operators position, and sig: naling mechanism at certain of said operators positions selectively responsive to the number of impulses in the various trains.

for indicating the kind of service for which the extended calling line is .adapted.

14. In a telephone system, the combination with a pluralit of telephone lines, of

identifyin means a apted to produce a plurality of c aracteristic electrical conditions,

each of said characteristic electrical condito the difi'erent characteristic electrical conditions of the different classes of lines, whereby calling lines of different classes are extended to different operators positions.

15. In a telephone system, the combination with a plurality ofi telephone lines divided into roups, of a devlce adapted to produce di erent characteristic groups of impulses and to apply said groups to the different groups, of lines to distinguish the lines of one group from the lines of another, operators positions, means for extending said lines to said operators positions, mechanism for controlling the extension of said lines to said positions, and an indicating de- -v1ce at one of said positions adapted to be brou ht temporarily into association with the clrcuit of an extended line, said indicating device and the aforesaid controlling mechanism being selectively responsive to said diflerent characteristic groups of impulses. v

16. In a telephone system, the combination with a plurality of lines divided into groups, of identifying means for producing a characteristic electrical condition in the lines of each group, mechanism for selectively controlling the extension of the circuits ofsaid lines, and a selective device associated with an extended line circuit, said controlling mechanism and said selective device both being selectively responsive to the characteristic electrical conditions produced by said identifying means.

17. In a telephone system, the combination with a plurality of telephone lines divided into groups, of a plurality of operators positions, a plurality of connecting trunks each of whichrhas access to all of said operators positions and each of which is accessible to all of said lines, and means for automatically efiecting the extension of the calling lines of each of sald groups to a particular and corresponding one of said operators positions.

18. The combination with a plurality of lines divided into classes with respect to the kind of service they are adapted to receive, said lines being intermingled irrespective of line groups of groups of cir cuits to which said lines are adapted to be extended, and means for automatically segregating calls from a particular class of said lines to a particular grou of said circuits. 19. The combination w1th a plurality of lines divided into classes with respect to the kind of service they are adapted to receive, of groups of connecting circuits to which said lines are adapted to be extended, a class-of-service identifying means for applying to the lines of each class a characteristic'electrical condition, and automatic segregating mechanism selectively responsive to said characteristic electrical conditions for directing the calls from a certain class of lines to a certain group of said connecting circuits.

20. The combination with a plurality of lines divided into classes with respect to the kind of service the lines are adapted to 'receive, of an identifying device for applying to the lines of each class a train of groups of impulses differing from the trains applied to the other classes in the number and time relation of the impulses in the groups, automatic segregating mechanism selectively responsive to the time relation of the impulses for directing the calls from a certain class of lines into certain paths and the calls from another class of lines into other paths, and elass-of-service indicating mechanism selectively responsive to the number of impulses in the groups of the various trains. I

21. The combination with a plurality of lines divided into classes with respect to the kind of service the lines are adapted to receive, of an identifying device for applying to the lines of each class a train of groups of impulses difiering from the trains applied to the lines of another class in the number 0t impulse in the groups, classof-service 1ndicat1n mechanism selectively responsive to the w ole number of impulses in any of the groups of each train, a plurality of operators positions, and automatic segregating mechanism responsive to less than the whole number of impulses in each group of a train for automatically directing the calls from the lines of a certain class to certain of said operators positions.

22. The combination with a plurality of lines divided into classes with respect to the kind of service the lines are adapted to receive, of a plurality of operators positions, means for extending said lines to said positions, means for automatically directin the calls from the lines of certain of said classes to a certain operators position, and means at said operators posit1on for automaticallv determining the class of the line from which a call is extended. 1

23. The combination with a plurality of groups of lines, of a device for producing a ,corresponding number of characteristic electrical conditions and applying a different one of such characteristic electrical conditions to the lines of each group, a plurality of operators positions, automatic segregating mechanism selectively respon sive to the characteristic electrical condition applied to certain of said groups of lines for extending the circuits of calling lines of those groups to one of said operators positions, and circuit controlling mechanism at said position selectively responsive to the characteristic electrical conditions of the classes of lines that are extended thereto.

24. The combination with a plurality of lines divided into classes, of an identifying device for applying to the lines of each class a'train of groups of impulses, each train dillering in the number of impulses in a group from the trains applied to the lines of the other classes, means for producing a train of test impulses, certain of said identifying trains diit'ering from other of said trains in the time relation between the impulses of the groups and said test impulses, automatic segre ating mechanism for extending the calls from the lines of certain classes into certain paths and the calls from the lines of other classes into other paths, said automatic segregating mechanism being selectively responsive to the diiiering time relations between said test impulses and the identifying impulses of the various trains, and mechanism associated with the circuits of the extended lines selectively responsive to the number of impulses in the roups of the various trains.

25. The combination with a plurality of lines divided into classes, said lines being intermingled irrespective of line groups of a lurality of operators positions for servmg said lines, and means for automatically giving the calling lines of one of said classes access to certain of said 0 erators positions and the calling lines 0? another class access to all of said operators positions.

26. The combination with a plurality of lines divided into classes 'with res ect to the kind of service they are adapte to receive, of a plurality of operators positions, a plurality of call extendin circuits for extending the circuits of sai lines to said operators positions, class-of-service identifying means for applying to the lines of each class a characteristic electrical condition for identifying the same, operators selecting apparatus controlling the extension of said call extending circuits to said operators positions, and automatic segregating mechanism responsive ,to the characteristic electrical condltion of a calling line and controlling the" operation of said operators selecting apparatus, said automatic segre-' gatin mec anism operating to give a certain c ass of lines access to certain of said operators positions and another class of lines access to all of said operators positions.

27. In a telephone system, the combination with a plurality of lines divided into groups,.of identifying means for producing a characteristic electrical condition in the lines of each group, and mechanism for selectively controlling the extension of the circuits of said lines, said controlling mechanism being selectively responsive to the characteristic electrical conditions produced by said identifying means.

In witness whereof, we hereunto subscribe .our names this 20th day of March A. D., 

